codeguard-rust

Rust Codeguard Gate

Goal: turn "looks fine" into repeatable tool evidence, and honestly distinguish between pass, fail, unable to verify, and planned.

Start in 30 seconds

1. At the repository root, confirm Cargo.toml or that the target file exists.
2. Detect tools:cargo --version。
3. Read-only check first:cargo clippy --all-targets -- -D warnings。
4. Classify results as: code violations, missing configuration, missing tools, tool internal errors.
5. Only perform on safely fixable items:cargo fmt。
6. Re-run lint, and run the project's existing test/build gates.

You can directly propose:

• "Check this Rust project, don't modify anything yet, and give me a classification of lint failures."
• "Only fix Rust formatting issues; list semantic issues first."
• "Verify Rust lint, test, and build evidence before committing."

Capability boundaries

✅ Good at handling

1. Based on .rs and project markers, identify the Rust workspace.
2. Execute cargo clippy --all-targets -- -D warnings and retain the exit code, scope, and tool version.
3. Distinguish between formatting, static rules, configuration, dependency, and environment-related failures.
4. Use cargo fmt to handle reversible issues and rescan.
5. Report local results separately from CI/build/test evidence.

⚠️ Requires conditions

1. The target tool must be installed and its version compatible with the project constraints.
2. It must be executed from the correct repository or module root directory.
3. If the project has custom configuration, the committed configuration takes precedence.
4. Whether generated code, vendor, and cache directories are scanned must follow repository rules.

❌ Not applicable

1. Do not treat formatter passing as compilation, testing, or security audit passing.
2. Do not silently install tools, upgrade dependencies, or modify team rules.
3. Do not use suppress/ignore/raising thresholds to hide real issues.
4. Do not claim "checks passed" when tools or configuration are missing.

When to use

• The user requests checking or fixing Rust code standards.
• AI modified .rs, and pre-commit verification is needed.
• CI shows failures related to cargo clippy --all-targets -- -D warnings .
• Need to determine whether an issue can be fixed automatically or must be handled manually.

When not to use

• When the main task is learning language syntax, framework design, or business modeling, use the corresponding language professional skill instead.
• When the main task is dependency vulnerabilities, security auditing, or license governance, use a dedicated security skill.
• When the user only asks to explain an error message and there is no project context, provide a local explanation first and do not claim the whole repository is green.

Data and security

This skill does not collect, upload, send, or store user code and credentials. By default, it only reads the local repository configuration and runs local tools; it does not install dependencies over the network, and does not record tokens, passwords, or private source code. Before any automatic fix, check the diff first; destructive or large-scale changes must be explicitly confirmed by the user.

Execution contract

Project	Current facts
Status	stable(since Codeguard V0.1)
File extensions	.rs
Project markers	Cargo.toml
Integration configuration	Cargo.toml
Tool readiness	Toolchain built in or declared by the project
Probe command	使用命令查找与项目配置检查
lint	cargo clippy --all-targets -- -D warnings
format/fix	cargo fmt
Project-level gate	cargo clippy --all-targets -- -D warnings

Standard Workflow

Step 1: Determine the real scope

Confirm the repository root, module roots, generated directories, vendor directories, and user-specified files. For multi-module projects, first list the modules that will be scanned; do not guess based on the current directory.

Step 2: Read the project contract

Read Cargo.toml and the actual commands in CI. Repository configuration takes precedence over the examples in this skill; if the two conflict, report the differences first.

Step 3: Probe tools and versions

Run 对应工具 --version. Missing tools, incompatible versions, or configurations that fail to load are all recorded as "unable to verify", not as passing.

Step 4: Run read-only checks

Run cargo clippy --all-targets -- -D warnings, recording the command, working directory, exit code, tool version, and the first actionable error.

Step 5: Failure classification

Type	Typical signals	Handling
Formatting	Indentation, whitespace, import order	Formatter allowed, then check the diff
Static rules	unused, complexity, naming, dangerous APIs	Minimal semantic fix; no bulk guessing
Configuration	parser/config/schema not found	Fix the integration or report the prerequisites
Environment	command not found, version conflicts	Report installation/version requirements; do not install silently
Tool internal error	crash, timeout, parser exception	Preserve the raw evidence and narrow the reproduction scope

Step 6: Controlled fixes

Prefer running cargo fmt. Only handle issues that are certain and reversible; dependency upgrades, rule exemptions, generated files, and business semantic changes must be explained separately.

Step 7: Verification loop

Re-run the same lint command, then run the project's existing tests and build. Only write "passing" when the command, scope, and exit code are all clear; otherwise write "not run" or "unable to verify".

Rules

1. Re-verify with the same command: After fixing, you must re-run the original command that triggered the failure.
2. Layered evidence: Report lint, format, compile, test, and security separately.
3. Minimal changes: Do not refactor along the way, and do not expand style fixes into business rewrites.
4. Configuration first: Do not override the project's existing ignore, dialect, target, or version constraints.
5. No fabrication: Tools not run, configurations not seen, and platforms not verified must be clearly marked.

Output template

Rust Codeguard 结果
- 范围：<仓库/模块/文件>
- 工具：<名称与版本>
- 命令：<实际命令>
- 状态：PASS / FAIL / UNVERIFIED / PLANNED
- 发现：<按格式/规则/配置/环境分类>
- 修改：<文件与原因；无修改写 none>
- 复验：<命令、退出码>
- 未验证：<测试/构建/平台差异>

Gotchas

1. Missing tools are not a pass — must output UNVERIFIED and explicit preparation steps.
2. A formatter is not a linter — all-green formatting cannot override static rule or compilation errors.
3. The root directory determines the result — Running in the wrong module may miss issues or load the wrong configuration.
4. Placeholders are not literal arguments — {file} and must be replaced with real, authorized paths.
5. Auto-fixes may enlarge the diff — After fixing, review the diff first, then run the regression gate.
6. Generated and vendor directories require an explicit policy — Do not scan or modify third-party content across the whole repository at will.

Domain pitfalls and fixes

1. Domain pitfall — cargo fmt Passing does not mean Clippy passes; formatting and semantic lint are two independent gates.
2. Domain pitfall — Workspace must be run from the root Cargo.toml , otherwise member crates may be missed.

When information is insufficient

Do not just say "please provide more information." First give a safe, read-only inspection plan and list the specific items that still need confirmation:

1. repository/module root directory;
2. target tools and versions;
3. project configuration files;
4. the authoritative commands in CI;
5. whether auto-fix is allowed.

FAQ

Q1: If the tool is not installed, can I conclude the code is fine? No. The status must be UNVERIFIED。

Q2: Can ignore or suppression be added automatically? No. Exemptions may only be granted when the user explicitly accepts them and the reason is recorded.

Q3: Why does it still fail after formatting? The formatter only covers formatting; static rules, configuration, compilation, and tests still need to be handled separately.

Q4: Should generated code be scanned? By default, follow the repository configuration; if there are no rules, exclude generated/vendor first, then explain to the user.

Q5: How can I avoid changing too much at once? Fix in batches by failure category and file first, and rerun the original command and review the diff for each batch.

Q6: If it passes locally, can I say CI will pass? No. You also need to align CI's versions, environment variables, operating system, and command scope.

Load resources on demand

• When encountering exit codes, failure classification, or exemption decisions, read references/rules/gate-rules.md。
• When you need to check this language's registry, toolchain, and project configuration, read references/tooling/toolchain.md。
• When you need copyable task examples, read by scenario examples/, and there is no need to load them all at once.